Explicit simultaneous enhancement of adhesion strength and wear resistance of functional value-added epoxy-functionalized rice husk ash nanoparticle composite coating

2020 ◽  
Vol 109 (7-8) ◽  
pp. 2205-2214
Author(s):  
V. S. Aigbodion
Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2709
Author(s):  
Mohd Salahuddin Mohd Basri ◽  
Faizal Mustapha ◽  
Norkhairunnisa Mazlan ◽  
Mohd Ridzwan Ishak

As a result of their significant importance and applications in vast areas, including oil and gas, building construction, offshore structures, ships, and bridges, coating materials are regularly exposed to harsh environments which leads to coating delamination. Therefore, optimum interfacial bonding between coating and substrate, and the reason behind excellent adhesion strength is of utmost importance. However, the majority of studies on polymer coatings have used a one-factor-at-a-time (OFAT) approach. The main objective of this study was to implement statistical analysis in optimizing the factors to provide the optimum adhesion strength and to study the microstructure of a rice husk ash (RHA)-based geopolymer composite coating (GCC). Response surface methodology was used to design experiments and perform analyses. RHA/alkali activated (AA) ratio and curing temperature were chosen as factors. Adhesion tests were carried out using an Elcometer and a scanning electron microscope was used to observe the microstructure. Results showed that an optimum adhesion strength of 4.7 MPa could be achieved with the combination of RHA/AA ratio of 0.25 and curing temperature at 75 °C. The microstructure analysis revealed that coating with high adhesion strength had good interfacial bonding with the substrate. This coating had good wetting ability in which the coating penetrated the valleys of the profiles, thus wetting the entire substrate surface. A large portion of dense gel matrix also contributed to the high adhesion strength. Conversely, a large quantity of unreacted or partially reacted particles may result in low adhesion strength.


2021 ◽  
Vol 31 (1) ◽  
pp. 27-32
Author(s):  
Daniel-Mkpume Cynthia Chikodi ◽  
Obikwelu Daniel Oray Nnamdi ◽  
Aigbodion Victor Sunday

This paper presents the anti-wear and hardness values of electrodeposited Zn-ZnO- XRHA composite coating. Chloride-based bath was employed for the deposition bath. The deposition parameters were 0g, 10g and 20g rice husk ash (RHA) particulate loading, 15 minutes deposition, 1.4A current, 400 rpm stirring rate and 75℃ bath temperature. The composition, morphology, occurred phases, hardness and wear resistance for the RHA, mild steel substrate and developed coatings were studied. Equipment used for analyzing the coatings properties were x-ray fluorescence spectrometer, scanning electron microscope (SEM) with attached energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), EMCO Test Dura-scan microhardness tester and CERT UMT-2 tribological tester. Results showed that the Zn-ZnO-20RHA coated substrate had the highest hardness result toping the bare substrate by about 170% increment value. The trend of the wear loss for the developed Zn-ZnO-XRHA descended relative to increased particulate loading.


Author(s):  
A. R. Valeeva ◽  
◽  
E. M. Gotlib ◽  
E. S. Yamaleeva ◽  
◽  
...  

The use of epoxy antifriction coatings can significantly reduce thermal stress in the friction zone and expand the coating working temperature interval while keeping high wear resistance. The paper considers the effect of non-activated and activated by surfactants silicate filler – rice husk ash on the physicochemical and mechanical properties of epoxy materials applied as antifriction coatings. All studied samples of rice husk ash, both initial and activated with surfactants, have an alkaline surface nature. The study identified that all cationic quaternary ammonium salts (QAS) reduce the pH of rice husk ash. At the same time, nonionic OXIPAV increases this indicator. Activation of the rice husk ash surface, both by the quaternary ammonium salts and aminosilanes, significantly reduces the porosity of this silicate. In this case, the average pore diameter does not change significantly, and their specific surface area decreases significantly, to a lesser extent, when activated by nonionic quaternary ammonium salts. The application of quaternary ammonium salts and aminosilanes in the amount of 33 % for activation of the surface of the investigated silicate filler reduces its modifying effect in epoxy compositions, regardless of the chemical structure of the surfactants used, which is not a typical effect. Therefore, the authors assumed that the suboptimal concentration of quaternary ammonium salts and aminosilanes was used. The study identified that the optimal concentration of 50 % alcohol solution of KATAPAV is 14.7–21 %. In this range of the QAS content, there is a significant increase in hardness (about 40 %), a slight decrease in wear (about 10 %), and a significant decrease in the coefficient of static friction (up to 2 times). At the same time, the authors observed an increase in adhesion to metal up to 3 times and bending strength up to 25 %. Thus, rice husk ash activated with an optimal amount of quaternary ammonium salts is an effective modifier of epoxy coatings, which improves their antifriction properties and increases wear resistance, hardness, strength, and adhesion characteristics.


2021 ◽  
Author(s):  
Tang Baoyu ◽  
Zhang Long ◽  
Yu Zaiqian

Abstract Rice husk ash derived from the rice husk, a renewable waste biomass resource from rice production can be used to produce high value-added silica materials with various applications. But present technologies suffer the shortages of using inorganic acid as the precipitating agent, complex salt-containing wastewater post-treatment, higher production cost, lower product quality, and without the recycling of process additives. In this paper, improved clean chemical precipitation characterizing of recycling the by-product and surfactant used is developed with the highest silica product yield of 99.3%, pore size (21-35 nm), and specific surface area (196-462 m2/g). After the by-product solution is reused 5 times, the yield of silica can still reach 99.1%. The recovery yield of surfactant is 95.3%. The properties of the prepared silica meet the standard of silica for specific applications. The process characterized the recycling of the by-product and surfactant in the process, greener CO2 precipitant, ensuring the greenness, process efficiency, and low production cost. This opens up a new industrialization practical way for up-grading utilization of waste biomass and CO2 containing industrial effluents.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1214
Author(s):  
Tzong-Horng Liou ◽  
Yuan Hao Liou

Rice husk is an agricultural biomass waste. Burning rice husks in an oxygenic atmosphere releases thermal energy and produces ash that is rich in silica. Rice husk ash (RHA) can be used as a sustainable source of silica for producing high-value-added products. In this study, mesostructural graphene oxide (GO)/SBA-15, a graphene-based hybrid material, was synthesized from RHA. The materials are inspected by Fourier transform infrared spectrometer, Raman spectrometer, field-emission scanning electron microscopy, transmission electron microscopy, surface area analyzer, and X-ray diffraction analyzer. Studies have revealed that GO/SBA-15 possesses various oxygen functional groups that are helpful for dye adsorption. The material consisted of high pore volume of 0.901 cm3/g, wide pores of diameter 11.67 nm, and high surface area of 499 m2/g. Analysis of the methylene blue (MB) adsorption behavior of GO/SBA-15 composites revealed that their adsorption capacity depended on the gelation pH, GO content, adsorbent dosage, and initial dye (MB) concentration. The highest adsorption capacity of GO/SBA-15 was 632.9 mg/g. Furthermore, the adsorption isotherms and kinetics of GO/SBA-15 were investigated. This study demonstrated the great advantage of treated RHA and the potential of this material for use in organic dye adsorption.


2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Miyuki Miyazaki ◽  
Takeshi Shiono

Rice husk (RH) is a biomass resource that contains about 20 mass% silica. In Southeast Asia countries, RH is used as fuel for thermal power plants, and it produces a large amount of ash (Rice Husk Ash: RHA), as industrial waste. Furthermore, our research group has reported that consolidated zeolite A could be prepared from RHA as a raw material. Zeolite A has hydrophilic micropore in the structure and is used for adsorption and a builder for detergent. From processing point of view, the remaining carbon must be removed before synthesizing of zeolite A. However, the utility of carbon in RHA has not been studied sufficiently. In the present study, therefore, the possibility of usage of both silica and carbon in RHA as a raw material was investigated for the high value-added application of RHA. Before the synthesis of zeolite, activation treatment of carbon was carried out for RHA under specific conditions to make the carbon become porous. The specific surface area was measured by BET for activated RHA. Additionally, hydrothermal treatments were attempted after adjusting the composition of raw materials for the preparation of composites of carbon and zeolite. For the obtained specimens, XRD analysis and SEM were conducted as characterizations to confirm crystalline phases and microstructures respectively. Activation treatment made the specific surface area of RHA larger. As the activation time and temperature increased, silica was crystallized to cristobalite and the reactivity was decreased. The crystalline phase of zeolite A was recognized in the specimens with an appropriate composition. Furthermore, the homogenous zeolite A particles with a size smaller than 1 μm were also observed. Therefore, activated carbon-zeolite composites could be synthesized from RHA.


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